RESOLVED CONFIGURATION CHANGED197647
Rendering of Nature.com's "enhanced pdf" is super laggy 
https://bugs.webkit.org/show_bug.cgi?id=197647
Summary Rendering of Nature.com's "enhanced pdf" is super laggy
Oliver Hunt
Reported 2019-05-06 21:54:33 PDT
When loading the following paper: https://www.nature.com/articles/s41562-019-0592-8.epdf?author_access_token=P8LH-dm6-WcTUPR6aO7-FtRgN0jAjWel9jnR3ZoTv0PVOC_Ht62aJdy448-TIs1vEHEgxWIZfw6lDOHNp_3r3y8VYCNboUTmS0nPEm2Ws4QGEioiesbzQ34zH5LxsHGwtK5wgRMj2M8LqvCcDgMkMg%3D%3D The performance is atrocious for a while. There's clearly an element of deferred loading impacting the performance, but in chrome the page starts scrolling after quite a delay, and then scrolls smoothly. In Safari, the scrolling remains extremely laggy, and fails to update. Per the inspector we're spending a lot of time in layout and rendering rather than js.
Attachments
instruments output (3.26 MB, application/zip)
2019-05-06 21:58 PDT, Oliver Hunt 		no flags
Details
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Oliver Hunt
Comment 1 2019-05-06 21:58:31 PDT
Created attachment 369230 [details] instruments output
Oliver Hunt
Comment 2 2019-05-06 22:08:08 PDT
Looks to be spending a tonne of time in/under/around CA::CG::draw_glyph_bitmaps(CA::CG::Renderer&, CA::CG::FillGlyphs const&, CA::CG::ShadowStyle const*, bool, bool) Instruments really should develop an understanding of dispatch queues.
Radar WebKit Bug Importer
Comment 3 2019-05-06 23:22:34 PDT
<rdar://problem/50529160>
Simon Fraser (smfr)
Comment 4 2019-05-08 09:19:52 PDT
The page seems to be very painting-heavy early on, then at some point get into a good state where it scrolls OK. Maybe rendering the pages lower down is triggering continual full repaints of the pages at the top.
Ahmad Saleem
Comment 5 2024-03-11 01:12:03 PDT
It seems to work fine now in Safari 17.4, is it still reproducible for anyone?
Karl Dubost
Comment 6 2024-03-11 05:35:38 PDT
working for me too.
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